Thermal hydrogen generator using a metal hydride and thermite

ABSTRACT

This invention relates to a thermal hydrogen generator and a process and system for generating hydrogen gas, more specifically to a process and system for generating hydrogen gas by thermally decomposing a metal hydride.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the benefits of U.S. ProvisionalApplication Ser. No. 61/701,721, filed Sep. 17, 2012, entitled “ThermalHydrogen Generator Using a Metal Hydride and Thermite”, which isincorporated herein by this reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The U.S. Government has a paid-up license in this invention and theright in limited circumstances to require the patent owner to licenseothers on reasonable terms as provided for by the terms of Contract No.FA9302-12-M-0001 awarded by the United States Air Force.

TECHNICAL FIELD

This invention relates to a thermal hydrogen generator and a process andsystem for generating hydrogen, more specifically to a process andsystem for generating hydrogen by thermally decomposing a metal hydride.

BACKGROUND OF INVENTION

Present methods to gather in-situ meteorological data include launchingconventional balloon-borne rawinsondes, launching dropsondes fromspecially-equipped aircraft, using a calibrated pacer air vehicle, orflying specific flight patterns. The major drawbacks affecting theseapproaches can include spatial inaccuracy (in the case of balloon-borneor falling sensors), asset availability (in the case of dedicatedmeasurement aircraft), and simple inefficiency. An in-situ radiosondesystem capable of deployment from nearly any military aircraft wouldsolve the problems of spatial inaccuracy, asset availability and simpleinefficiency by allowing for the spatially and temporally precisedeployment of sensors in the test airspace without placing any undueburden on other range assets or requiring additional flight time fromthe test aircraft.

One solution involves a system that is compatible with a countermeasuresdispensing system and flare magazine that employ components common withcurrent decoys and that follow the same trajectory upon deployment.These systems would be capable of operation as either a dropsonde orupsonde (rawinsonde), enabling measurements above or below the launchaircraft flight path; measure meteorological variables includingpressure, temperature, relative humidity, and winds (the latter viaGPS); and return data via one or more data link paths to eitheraircraft- or ground-based receivers.

The system would thus include an easily-deployed sonde which can eitherfall below (dropsonde) or rise above (upsonde) the flight path of thedeploying aircraft, such as an F-16. Aircraft-based deployment ensurestimely and spatially precise deployment of sensors. Furthermore, byusing common countermeasures systems as the deployment mechanism,readily available chase aircraft can be used to gather themeteorological data immediately before a test.

Several challenges are faced in the deployment of sondes fromcountermeasure dispensing systems. The first challenge is thatcountermeasure systems are small due to the limited space on militaryaircraft. Another challenge in the development of a upsonde system isthe necessity of being able to rapidly fill a balloon, such as a weatherballoon, with hydrogen gas (H₂) so that the upsonde can begin risingimmediately after being deployed from the aircraft.

Hydrogen gas (H₂) is the gas of choice for filling sondes. There aremany ways to form hydrogen gas, and the selection of the gas generationmethod can depend on the specific application for which the gas is beinggenerated. While few applications have a need to generate the gasquickly and from a housing as small as the countermeasures system, thereis still another application with strict constraints, namelyman-portable applications. There are many remote areas in the worldwhere it is impractical or impossible to transport hydrogen or heliumcylinders, or set up hydrogen generators. Furthermore, in some cases, asingle person may be charged with launching meteorological balloons fromareas reached only on foot or by parachuting into a location. In such asituation, the most compact and light-weight hydrogen generator possibleis required.

Several hydrogen-generating technologies have been considered for therapid generation of hydrogen gas, particularly for use in meteorologicalballoons.

The electrolysis of water can generate hydrogen to fill balloons. Keydisadvantages of this approach include the need for external electricalpower, pure water, size and weight of the equipment, and the relativelyslow rate of the electrolytic reaction. A remote electrolysis systemwould require batteries and water to generate hydrogen gas to fill aballoon.

Methanol can be catalytically reformed, usually in the presence ofwater, to produce a mixture of hydrogen and either carbon monoxide orcarbon dioxide. The resulting gas can be used as-is or the hydrogen canbe separated to fill a meteorological balloon. Disadvantages of thisapproach include the size and weight of the equipment, and the need forprecise thermal control of the catalytic reactor. The catalytic reactionoccurs at about 230 degrees Celsius, which is a reasonable temperatureto achieve. However, several problems present themselves with regard toa miniaturized approach, including maintaining the catalyst conditioningin storage (such as, kept under a hydrogen atmosphere), having a largeenough reactor bed to achieve sufficiently fast hydrogen generation,driving a methanol/water solution through the reactor bed, andpreheating the methanol/water solution to a vapor at 230 degreesCelsius.

Ammonia can be catalytically decomposed to yield hydrogen and nitrogen;this approach has been used for generating hydrogen at remote sitesbecause it is easier to ship ammonia than hydrogen. Key disadvantages ofthis approach include size and weight of the equipment, as well as thecomparatively demanding need to store ammonia in liquid forms in caseswhere volume is at a premium. Furthermore, catalytic decomposition ofammonia to nitrogen and hydrogen was examined, but either requires hightemperatures (approximately 350 degrees Celsius) or relies on novel,still-experimental catalysts active at lower temperatures.

What is needed is a method and system that can generate hydrogen gasvery quickly and fit in a very small volume. While methods to simplygenerate hydrogen gas are many, none of the systems can generatehydrogen gas rapidly from a lightweight, small volume system.

SUMMARY

Embodiments and configurations of the present invention can addressthese and other needs.

The present disclosure can include a device having a first compartmentcontaining a pyrotechnic composition, a second compartment containing ametal hydride, and a separator in thermal contact with the first andsecond compartments. The first and second compartments can separatelyand individually comprise one of steel, aluminum, ceramic, or otherheat-resistant materials alone or in combination.

The pyrotechnic composition can be a mixture of a powder metal oxide anda powder metal. The powder metal oxide can be selected from the groupconsisting essentially of iron (III) oxide (Fe₂O₃), iron (II,III) oxide(Fe₃O₄), copper (I) oxide (Cu₂O), copper (II) oxide (CuO), tin (IV)oxide (SnO₂), lead (IV) oxide (PbO₂), manganese (IV) oxide (MnO₂),manganese (III) oxide (Mn₂O₃), chromium (III) oxide (Cr₂O₃), cobalt (II)oxide (CoO), nickel (II) oxide (NiO), and vanadium (V) oxide (V₂O₅), andmixtures thereof. In some configurations, the powder metal is aluminum(Al), and in other configurations the powder metal may be magnesium (Mg)or zinc (Zn). In some configurations, the powder metal is selected fromthe group consisting of aluminum (Al), magnesium (Mg), zinc (Zn), andcombinations and composites thereof.

The separator can transfer thermal energy generated in the firstcompartment by reaction of the pyrotechnic composition to the secondcompartment. The separator can be comprised of steel or anotherheat-resistant, thermally conductive material, or alternatively ceramicor another heat-resistant, thermally insulating material as long as aseparate heat transfer path is provided.

At least some of the thermal energy can be transferred to the secondcompartment, thereby thermally decomposing at least some of the metalhydride to release hydrogen gas. The metal hydride can be selected fromthe group consisting essentially of lithium aluminum hydride (LiAlH₄),sodium aluminum hydride (NaAlH₄), potassium aluminum hydride (KAlH),lithium borohydride (LiBH₄), sodium borohydride (NaBH₄), potassiumborohydride (KBH₄), lithium hydride (LiH), sodium hydride (NaH),potassium hydride (KH), magnesium hydride (MgH₂), calcium hydride (CaH₂)and mixtures thereof. In some applications, the device can release, inno more than about 60 seconds, more than about 4.6 moles of hydrogen gasper liter of the device volume. In other applications, it can release,in no more than about 60 seconds, about 6.2 moles of hydrogen gas perliter of the device volume, and in yet still other applications it canrelease more than about 7.3 moles of hydrogen gas per liter of thedevice volume. In some applications, it can release, in no more thanabout 60 seconds, about 9.7 moles of hydrogen gas per liter of thedevice volume. In yet other applications, it can release, in about 300seconds, from about 4.6 to about 6.2 moles of hydrogen gas per liter ofthe device volume.

The device can further include an igniter interconnected with the firstcompartment. The igniter causes the ignition of the pyrotechniccomposition. The igniter can cause ignition by one or more of a spark,thermal energy (such as that from a hot wire), flame, or friction. Theigniter will typically use the initiation action to ignite a secondarymaterial which burns hot enough to ignite the thermite.

The present disclosure can provide a process for using the device. Theprocess can have the steps of: (a) initiating, in a first compartment,ignition of a pyrotechnic composition comprising powder aluminum and apowder metal oxide to release thermal energy; (b) transferring thereleased thermal energy from the first compartment to a secondcompartment containing a metal hydride; and (c) with the thermal energytransferred to the second compartment, initiating the thermaldecomposition of the metal hydride to release hydrogen gas.

The transferring step (b) may further include transferring the thermalenergy through one or both of a metal and metal-bearing compound.Furthermore, the transferring of the released thermal energy may includean intermediate heat conductor. In some configurations, one or moretungsten rods form the intermediate conductor.

The process can further include cooling the released hydrogen gas.

In some applications, the process can include releasing, in no more thanabout 60 seconds, more than about 4.6 moles of hydrogen gas per liter ofthe device volume. In other applications, the process can includereleasing, in no more than about 60 seconds, about 6.2 moles of hydrogengas per liter of the device volume, and in yet other applications morethan about 7.3 moles of hydrogen gas per liter of the device volume. Insome applications, the process can include releasing, in no more thanabout 60 seconds, about 9.7 moles of hydrogen gas per liter of thedevice volume. In yet other applications, the process can includereleasing, in about 300 seconds, from about 4.6 to about 6.2 moles ofhydrogen gas per liter of the device volume.

The present disclosure can include a sonde device having a balloon; aself-contained hydrogen generator a) interconnected to the balloon, b)configured to inflate the balloon after being launched from a militaryaircraft, and c) having a thermal separator positioned between and inthermal contact with i) a thermal compartment containing a thermitecomposition comprising a powder metal oxide and powder aluminum metal,ii) a gas-generating compartment containing a metal hydride, and iii) anigniter configured to ignite the thermite on launch from a conventionaldecoy flare ignition train of the military aircraft; and a datacollection module that is configured to collect data using amicroprocessor executable set of instructions on a tangible andnon-transient computer readable media for determining one or both ofmeteorological and terrestrial activities or conditions.

The reaction of thermite can generate thermal energy. At least some ofthe thermal energy generated in the thermal compartment by the reactionof the thermite can be transferred to the gas-generating compartment bythe thermal separator. In some applications, the thermal separator is ametal sheet. In some applications, the thermal compartment includes acrucible wrapped with a ceramic insulation.

The self-contained hydrogen generator can be configured to inflate theballoon with hydrogen released by thermal decomposition of the metalhydride contained in the gas-generating compartment. Furthermore, thethermite composition can be configured to generate sufficient thermalenergy to thermally decompose at least some of the metal hydride andrelease sufficient hydrogen to inflate the balloon. The metal hydridecan be selected from the group consisting essentially of lithiumaluminum hydride (LiAlH₄), sodium aluminum hydride (NaAlH₄), potassiumaluminum hydride (KAlH₄), lithium borohydride (LiBH₄), sodiumborohydride (NaBH₄), potassium borohydride (KBH₄), lithium hydride(LiH); sodium hydride (NaH), potassium hydride (KH), magnesium hydride(MgH₂), calcium hydride (CaH₂) and mixtures and composites thereof. Thepowder metal oxide can be selected from the group consisting essentiallyof iron (III) oxide (Fe₂O₃), iron (II,III) oxide (Fe₃O₄), copper (I)oxide (Cu₂O), copper (II) oxide (CuO), tin (IV) oxide (SnO₂), lead (IV)oxide (PbO₂), manganese (IV) oxide (MnO₂), manganese (III) oxide(Mn₂O₃), chromium (III) oxide (Cr₂O₃), cobalt (II) oxide (CoO), nickel(II) oxide (NiO), and vanadium (V) oxide (V₂O₅), and mixtures thereof.In some configurations, the powder metal is aluminum (Al), and in otherconfigurations the powder metal may be magnesium (Mg) or zinc (Zn). Insome configurations, the powder metal is selected from the group ofzero-valent metals consisting of aluminum (Al), magnesium (Mg), zinc(Zn), and combinations and composites thereof.

In some configurations, the thermal and gas-generating compartments arestacked one-on-top of another. In other configurations, the thermal andgas-generating compartments are arranged with one partly or completelyencased in the other.

The present disclosure can provide a number of advantages depending onthe particular configuration. It can provide a method and system thatcan generate hydrogen gas very quickly and fit in a very small volume.The system can therefore be small and lightweight. Thehydrogen-generating system and method is therefore highly beneficial forrapidly filling meteorological balloons.

These and other advantages will be apparent from the disclosure of theaspects, embodiments, and configurations contained herein.

The term “automatic” and variations thereof, as used herein, refers toany process or operation done without material human input when theprocess or operation is performed. However, a process or operation canbe automatic, even though performance of the process or operation usesmaterial or immaterial human input, if the input is received beforeperformance of the process or operation. Human input is deemed to bematerial if such input influences how the process or operation will beperformed. Human input that consents to the performance of the processor operation is not deemed to be “material”.

The term “computer-readable medium” as used herein refers to any storageand/or transmission medium that participate in providing instructions toa processor for execution. Such a medium is commonly tangible andnon-transient and can take many forms, including but not limited to,non-volatile media, volatile media, and transmission media and includeswithout limitation random access memory (“RAM”), read only memory(“ROM”), and the like. Non-volatile media includes, for example, NVRAM,or magnetic or optical disks. Volatile media includes dynamic memory,such as main memory. Common forms of computer-readable media include,for example, a floppy disk (including without limitation a Bernoullicartridge, ZIP drive, and JAZ drive), a flexible disk, hard disk,magnetic tape or cassettes, or any other magnetic medium,magneto-optical medium, a digital video disk (such as CD-ROM), any otheroptical medium, punch cards, paper tape, any other physical medium withpatterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, a solidstate medium like a memory card, any other memory chip or cartridge, acarrier wave as described hereinafter, or any other medium from which acomputer can read. A digital file attachment to e-mail or otherself-contained information archive or set of archives is considered adistribution medium equivalent to a tangible storage medium. When thecomputer-readable media is configured as a database, it is to beunderstood that the database may be any type of database, such asrelational, hierarchical, object-oriented, and/or the like. Accordingly,the disclosure is considered to include a tangible storage medium ordistribution medium and prior art-recognized equivalents and successormedia, in which the software implementations of the present disclosureare stored. Computer-readable storage medium commonly excludes transientstorage media, particularly electrical, magnetic, electromagnetic,optical, magneto-optical signals.

The terms “determine”, “calculate” and “compute,” and variationsthereof, as used herein, are used interchangeably and include any typeof methodology, process, mathematical operation or technique.

The term “module” as used herein refers to any known or later developedhardware, software, firmware, artificial intelligence, fuzzy logic, orcombination of hardware and software that is capable of performing thefunctionality associated with that element.

Unless otherwise noted, all component or composition levels are inreference to the active portion of that component or composition and areexclusive of impurities, for example, residual solvents or by-products,which may be present in commercially available sources of suchcomponents or compositions.

All percentages and ratios are calculated by total composition weight,unless indicated otherwise.

It should be understood that every maximum numerical limitation giventhroughout this disclosure is deemed to include each and every lowernumerical limitation as an alternative, as if such lower numericallimitations were expressly written herein. Every minimum numericallimitation given throughout this disclosure is deemed to include eachand every higher numerical limitation as an alternative, as if suchhigher numerical limitations were expressly written herein. Everynumerical range given throughout this disclosure is deemed to includeeach and every narrower numerical range that falls within such broadernumerical range, as if such narrower numerical ranges were all expresslywritten herein. By way of example, the phrase from about 2 to about 4includes the whole number and/or integer ranges from about 2 to about 3,from about 3 to about 4 and each possible range based on real (e.g.,irrational and/or rational) numbers, such as from about 2.1 to about4.9, from about 2.1 to about 3.4, and so on.

The preceding is a simplified summary of the disclosure to provide anunderstanding of some aspects of the disclosure. This summary is neitheran extensive nor exhaustive overview of the disclosure and its variousaspects, embodiments, and configurations. It is intended neither toidentify key or critical elements of the disclosure nor to delineate thescope of the disclosure but to present selected concepts of thedisclosure in a simplified form as an introduction to the more detaileddescription presented below. As will be appreciated, other aspects,embodiments, and configurations of the disclosure are possibleutilizing, alone or in combination, one or more of the features setforth above or described in detail below.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are incorporated into and form a part of thespecification to illustrate several examples of the present disclosure.These drawings, together with the description, explain the principles ofthe disclosure. The drawings simply illustrate preferred and alternativeexamples of how the disclosure can be made and used and are not to beconstrued as limiting the disclosure to only the illustrated anddescribed examples. Further features and advantages will become apparentfrom the following, more detailed, description of the various aspects,embodiments, and configurations of the disclosure, as illustrated by thedrawings referenced below.

FIGS. 1A and 1B depict a device according to some embodiments of thepresent disclosure;

FIG. 2 depicts a process according to some embodiments of the presentdisclosure;

FIGS. 3A and 3B depict another device for generating hydrogen gasaccording to some embodiments of the present disclosure;

FIGS. 4A and 4B depict another device for generating hydrogen gasaccording to some embodiments of the present disclosure; and

FIG. 5 depicts yet another device for generating hydrogen gas accordingto some embodiments of the present disclosure.

DETAILED DESCRIPTION

A device for generating hydrogen gas is described herein. Compared toother hydrogen producing technologies, the device can be more compactand produce hydrogen gas more rapidly.

FIGS. 1A and 1B depict non-limiting configurations of a hydrogengenerator device 100. The hydrogen generator device 100 comprises afirst compartment 101 containing a pyrotechnic composition and a secondcompartment 102 containing a hydride. The first 101 and second 102compartments typically have a wall 111 and a separator 103. Theseparator 103 is in thermal contact with the first 101 and second 102compartments. Thermal energy generated in the first compartment 101 byreaction of the pyrotechnic composition is transferred to the secondcompartment 102 by the separator 103, whereby at least some of thethermal energy transferred to the second compartment 102 thermallydecomposes at least some of the hydride to release hydrogen gas.Typically, the hydride comprises a metal hydride.

The first 101 and second 102 compartments have first and secondcompartments volumes, respectively. The hydrogen generator device 100has a device volume. In some configurations the device volume can be thesum of the first 101 and second 102 compartment volumes. In someconfigurations, the device volume can be at more than the sum of thefirst 101 and second 102 compartment volumes. In some configurations,the first 101 and second 102 compartments can be stacked one-on-top ofthe other as depicted without limitation in FIG. 1A. It can beappreciated that they can be stacked in any order. In otherconfigurations, the first 101 and second 102 compartments can bearranged with one of the compartments partly or completely encased inthe other, as for example depicted without limitation in FIG. 1B. One orboth of first 101 and second 102 compartments may be comprised ofseparately and independently, one or more of steel, aluminum, orceramic.

In some embodiments, the first compartment 101 is configured with one ormore vents (not depicted).

In accordance with some embodiments, the first compartment may furthercomprise a crucible 110. Commonly, the pyrotechnic composition iscontained and reacts in crucible 110. The crucible 110 may comprise ametal or ceramic material. Commonly, the crucible 110 comprises one orboth of metal and ceramic materials having a melt temperature of morethan about 1,900 degrees Celsius. Suitable materials for the separator103 may comprise steel or other heat-resistant, thermally conductivematerials, or alternatively a ceramic or other heat-resistant, thermallyinsulating material as long as a separate heat transfer path isprovided. In some configurations, the first compartment 101 can furtherinclude a layer of ceramic insulation 112 positioned between the wall111 and crucible 110.

The pyrotechnic composition can comprise a powder metal oxide and apowder metal. The powder metal oxide can be selected from the groupconsisting essentially of iron (III) oxide (Fe₂O₃), iron (II,III) oxide(Fe₃O₄), copper (I) oxide (Cu₂O), copper (II) oxide (CuO), tin (IV)oxide (SnO₂), lead (IV) oxide (PbO₂), manganese (IV) oxide (MnO₂),manganese (III) oxide (Mn₂O₃), chromium (III) oxide (Cr₂O₃), cobalt (II)oxide (CoO), nickel (II) oxide (NiO), and vanadium (V) oxide (V₂O₅), andmixtures thereof. In some configurations, the powder metal is aluminum(Al), and in other configurations the powder metal may be magnesium (Mg)or zinc (Zn).

In one particular configuration, the pyrotechnic composition comprises amixture of powder ferric oxide and powder aluminum. Those of ordinaryskill in the art of pyrotechnics typically refer to this mixture offerric oxide and aluminum as thermite. The thermite chemical reaction isshown below in chemical equation (1):Fe₂O₃(s)+2Al(s)→2Fe(s)+Al₂O₃(s)  (1)The thermite chemical reaction is exothermic and releases an immenseamount of thermal energy. The thermal energy released by the thermitereaction is so intense that it products an aluminum oxide slag andmolten iron. The enthalpy or heat of reaction (ΔH° value) for thethermite reaction is about −849 kJ (e.g., −849 kJ per mole Fe₂O₃). Thethermite reaction does not require external oxygen and can, therefore,proceed in locations with limited or no air flow, or even under water.Similar reactions can be performed between aluminum and other ironoxides, copper oxides, manganese oxides, and various other metal oxides.It can be appreciated that in some embodiments, the thermite reactionand similar reactions between a powder metal and a powder metal oxidecan occur in the absence of any oxygen or oxidizing substance other thanthe powder metal oxide(s). Furthermore, the thermite reaction does notproduce any gases which might carry away some of the heat of thereaction or produce an explosive excess of pressure.

It can be appreciated that the pyrotechnic composition can generateimmense amounts of thermal energy per mass of the pyrotechniccomposition. A compact thermal energy generating system can be achievedby having such an immense amount of thermal energy per mass of thepyrotechnic composition. Furthermore, substantially most of heatgenerated remains available for use since gaseous byproducts are notproduced; that is, most of the heat is retained in the liquid and/orsolid reaction products as a source of thermal energy. Another way ofshowing the advantages of having a high temperature (thermal energy) permass can be found through an analysis of the following equation:Q=mcΔT  (2)where Q is thermal energy, ΔT is the temperature change, m is mass ofmaterial undergoing the temperature, and c is the heat capacity of thematerial undergoing the temperature change. So, to minimize the mass ofmaterial (the pyrotechnic composition and/or is reaction byproducts) andimplicitly the volume of the device, the only factor available toincrease the heat of thermal energy available (Q) to the system (thedevice) is to increase ΔT, as the heat capacity (c) of the system isassumed to be constant or at least not adjustable over a meaningfullyvariable range. That, in turn, means a high starting temperature is verybeneficial. An additional benefit of a high starting temperature is thatheat transfer rate is directly proportional to temperature difference.Higher temperatures will lead to faster heat transfer, which in turnleads to faster decomposition reactions and hydrogen production.

Typically, at least some of the thermal energy transferred to the secondcompartment 102 by the separator 103 thermally decomposes some of themetal hydride contained in the second compartment 102. The thermaldecomposition of the metal hydride releases hydrogen gas. Morespecifically, the thermal decomposition of the metal hydride chemicallyconverts at least some, if not at least most, of the hydrogen containedin the metal hydride to hydrogen gas. By way of non-limiting example,lithium aluminum hydride (LiAlH₄) can be thermally decomposed in aseries of reactions to yield hydrogen gas:3LiAlH₄(s)→Li₃AlH₆(s)+2Al(s)+3H₂(g)  (3)2Li₃AlH₆(s)→>6LiH(s)+2Al(s)+3H₂(g)  (4)2LiH(s)+2Al(s)→2LiAl+H₂(g)  (5)

The reactions depicted by chemical equations 3, 4 and 5, respectively,occur in the range of 150-175 degrees Celsius, with a ΔH° value of +9.79kJ (experimental), at about 200° C., with a ΔH° value of +94.32 kJ(experimental), and at about 400 degrees Celsius, with a ΔH° of no morethan about +181 kJ (based thermodynamic calculations). It can beappreciated that the greater the reaction temperature the greater theconversion of the hydride to hydrogen gas.

Generally, at least about 10 mole % of the hydrogen in the form of ahydride contained in the metal hydride is converted to hydrogen gas.More generally, at least 20 mole %, even more generally at least about30 mole %, yet even more generally at least about 40 mole %, still yeteven more generally at least about 50 mole %, still yet even moregenerally at least about 60 mole %, yet even more generally at leastabout 70 mole %, still yet even more generally at least about 80 mole %,still yet even more generally at least about 90 mole %, still yet evenmore generally at least about 95 mole %, or yet still even moregenerally at least about 99 mole % of the hydrogen in the form of ahydride contained in the metal hydride is converted to hydrogen gas.Commonly, at least about 80 mole % of the hydrogen in the form of ahydride contained in the metal hydride is converted to hydrogen gas.

While not wanting to be limited by these examples, thehydrogen-generating device commonly generates, in no more than about 60seconds, more than about 4.6 moles of hydrogen gas per liter of thedevice volume. More commonly, the hydrogen-generating device commonlygenerates, in no more than about 60 seconds, more than about 7.3 molesof hydrogen gas per liter of the device volume. According to someconfigurations, the hydrogen-generating device typically generates, inno more than about 60 seconds, from about 6.2 to about 9.7 moles ofhydrogen gas per of the device volume. Moreover, in accordance with someconfigurations, the hydrogen-generating device typically generates, inabout 300 seconds, from about 4.6 to about 6.2 moles of hydrogen gas perliter of the device volume. It can be appreciated that there is no needto control one or both of the temperature or thermal energy transferwithin the device 100. As a result, the device 100 can be configured totransfer thermal energy rapidly between the first 101 and second 102compartments, thereby decomposing the metal hydride to release hydrogengas more rapidly than current hydrogen generation systems. Moreover, thedevice 100 can be more easily constructed and operated than otherhydrogen generators. As for example, there is no need to have the metalhydride reaction occur at any specific temperature, so neither reactionof the pyrotechnic composition nor the transfer of thermal energy fromthe first 101 to the second 102 compartment is regulated. This is incontrast to catalytic decomposition methods, which require the catalystto be operated at specific temperatures, pressures, and reactant flowrates.

The gas generator was designed to require only the first two reactionsto go to completion with the result that only temperatures ofapproximately 200 degrees Celsius would need to be reached. Any excessheat reaching the system will simply cause the temperature to rise, andpotentially induce the formation of some excess hydrogen via abovereaction 5.

Returning to the separator 103, the separator 103 can pass at least mostof the thermal energy generated in the first compartment to the secondcompartment. Commonly, the separator 103 transfers more than about 30%of the thermal energy generated by reaction of the pyrotechniccomposition. More commonly, it transfers more than about 40% of thethermal energy, even more commonly more than about 50% of the thermalenergy, yet even more commonly more than about 65% of the thermalenergy, still yet even more commonly more than about 75% of the thermalenergy, still yet even more commonly more than about 85% of the thermalenergy, or yet still even more commonly more than about 95% of thethermal energy generated by reaction of the pyrotechnic composition.

The separator 103 can comprise any metal or ceramic material having amelt temperature more than about 1,000 degrees Celsius. Typically, theseparator 103 has a melt temperature more than about 1,500 degreesCelsius, more typically a melt temperature more than 1,900 degreesCelsius. Suitable materials for the separator 103 may comprise steel oranother heat-resistant, thermally conductive material, or alternativelyceramic or another heat-resistant thermally insulating material as longas a separate heat transfer path is provided.

In accordance with some embodiments, such as where the separator 103 isfabricated from a thermal insulator, the separator 103 may include anintermediate thermal energy conductor 105. The intermediate thermalenergy conductor 105 can transfer at least some the released thermalenergy from the first compartment 101 to a second compartment 102.Typically, the intermediate thermal energy conductor 105 comprises oneor more of rods, vanes, blades, fins, and bars. Commonly, theintermediate thermal energy conductor 105 traverses through theseparator 103 with one distal end of extending into the firstcompartment 101 and the other distal end extending into the secondcompartment 102. Suitable materials for the intermediate thermal energyconductor 105 can include tungsten and tungsten carbide. In someconfigurations, the intermediate thermal energy conductor 105 comprisesone or more tungsten carbide rods. While not wanting to be bound by anyparticular example, the thermal energy conductor 105 has a melting pointhigher than 2,200 K (1,927 degrees Celsius), and a high thermalconductivity of more than about 100-200 W/m-K. In accordance with someconfigurations, the thermal energy conductor 105 has a thermalconductivity of more than about 200 W/m-K.

The hydrogen generator device 100 may further include an igniter 104interconnected with the first compartment. The igniter 104 causes theignition of the pyrotechnic composition. In some configurations, a sparkgenerated within the igniter 104 initiates the ignition process. Inother configurations, the ignition process is initiated by thermalenergy generated within the igniter 104. The thermal energy providedwithin igniter 104 may be from a hot wire. In other configurations, theinitiating energy within igniter 104 may be from flame. In otherconfigurations, the initiating energy within the igniter 104 may beprovided by friction. In accordance with some embodiments, the igniter104 may comprise a bore-rider pin and ignition pellet utilized in someflare technologies. Details of the bore-rider switch and ignition pelletare described in U.S. Pat. No. 7,363,861, which is incorporated hereinby this reference in its entirety.

The igniter 104 may further comprise an ignition aperture in the firstcompartment 101. The ignition aperture may be configured with asafety-delay switch system.

The hydrogen generator device 100 may further include a heat exchanger106 interconnected with the second compartment 102. The heat exchanger106 is configured to cool the hydrogen gas released from the hydride. Inaccordance with some embodiments, the heat exchanger 106 isinterconnected to outlet 107 of the second compartment 102. Theexchanger 106 cools the hydrogen gas exiting the second compartment 102through outlet 107.

The sonde device can include a data collection module that is configuredto collect data for determining one or both of meteorological andterrestrial activities or conditions.

The sonde device can include a data collection module that is configuredto collect data using a microprocessor executable set of instructionsstored on a tangible and non-transient computer readable media fordetermining one or both of meteorological and terrestrial activities orconditions. The data collection module can be located on the balloonsonde and configured to transmit the sensed information and results to abase unit. Alternatively, it could be located in the base unit and be inwireless communication with one or more sensors on the balloon sonde.Measured events or sensed information can include atmosphere;temperature, air pressure, water vapor, and spatial position with theprocessed data derived therefrom being, for example, the gradients andinteractions of each event and how the event(s) change(s) in time.Techniques to process data are well known in the disciplines ofatmospheric science (e.g., meteorology, climatology, atmosphericchemistry) and hydrology and the interdisciplinary fields ofhydrometeorology and ocean-atmosphere studies, among others. Thesensor(s) used to collect the sensed information can include ahygrometer, thermometer, barometer, and satellite positioning systemreceiver.

FIG. 2 depicts a process 200 for using the hydrogen generator device100.

In step 210, reaction of a pyrotechnic composition is initiated in afirst compartment 101. The reaction releases thermal energy. Thepyrotechnic composition comprises powder aluminum and powder metaloxide. Non-limiting examples of the powder metal oxide can be selectedfrom the group consisting essentially of iron (III) oxide (Fe₂O₃), iron(II,III) oxide (Fe₃O₄), copper (I) oxide (Cu₂O), copper (II) oxide(CuO), tin (IV) oxide (SnO₂), lead (IV) oxide (PbO₂), manganese (IV)oxide (MnO₂), manganese (III) oxide (Mn₂O₃), chromium (III) oxide(Cr₂O₃), cobalt (II) oxide (CoO), nickel (II) oxide (NiO), and vanadium(V) oxide (V₂O₅), and mixtures thereof. Non-limiting examples of thepowder metal can be selected from the group consisting of aluminum (Al),magnesium (Mg) or zinc (Zn).

Step 210 may further include contacting the pyrotechnic composition withan igniter to initiate the reaction. In some configurations the reactionmay be initiated by contacting the igniter with one of a hot wire or aspark. In other configurations, flame may initiate the reaction of thepyrotechnic composition via the igniter. In yet other configurations,friction may initiate reaction of the pyrotechnic composition via theigniter. In yet other configurations, a conventional decoy flareignition train ignites the reaction of the pyrotechnic composition. Thatis, the sequencer, ignition pellet, and first fire coat as used forconventional MJU-10 flares can be used to ignite the reaction. This putsthe ignition of the reaction under the identical timing and control of aregular flare process, greatly improving reliability, consistency, andsafety.

In step 220, the energy released by the reaction of the pyrotechniccomposition is transferred the first compartment 101 to a secondcompartment 102. A metal hydride is contained in the second compartment.Non-limiting examples of the metal hydride may be selected from thegroup consisting of lithium aluminum hydride (LiAlH₄), sodium aluminumhydride (NaAlH₄), potassium aluminum hydride (KAlH₄), lithiumborohydride (LiBH₄), sodium borohydride (NaBH₄), potassium borohydride(KBH₄), lithium hydride (LiH); sodium hydride (NaH), potassium hydride(KH), magnesium hydride (MgH₂), calcium hydride (CaH₂) and mixtures andcomposites thereof.

In step 230, the thermal energy transferred to the second compartment102 decomposes the metal hydride to release hydrogen gas. The hydrogengas is commonly released at rate of more than about 4.6 moles ofhydrogen gas per liter of the device volume per minute. More commonly,the hydrogen-generating device commonly releases more than about 7.3moles of hydrogen gas per liter of the device volume per minute.According to some embodiments, the hydrogen-generating device typicallyreleases, in less than one minute, from about 6.2 to about 9.7 moles ofhydrogen gas per liter of the device volume. Moreover, in accordancewith some configurations, the hydrogen-generating device typicallyreleases from about 4.6 to about 6.2 moles of hydrogen gas per liter ofthe device volume per 300 seconds.

Step 230 may further include; transferring the released thermal energyfrom the first compartment 101 to the second compartment 102 through aseparator 103. Moreover, some embodiments may further includetransferring at least some of the released thermal energy from the firstcompartment 101 to a second compartment 102 through an intermediatethermal energy conductor 105. In some configurations, the intermediatethermal energy conductor 105 comprises one or more tungsten carbiderods.

In optional step 240, the released hydrogen gas is cooled. The releasedhydrogen gas may be cooled by a heat exchanger.

In optional step 250, the released gas may be used for one of: inflationof a meteorological balloon; inflation of other types of balloons;inflation of a blimp; inflation of an inflatable article; orpressurization of a gas storage cylinder.

FIGS. 3A and 3B depict a device for generating hydrogen gas according tovarious embodiments as described in the above Summary and DetailedDescription and herein below. More specifically, FIGS. 3A and 3B depicta device 100 having first 101 and second 102 compartments stackedone-on-top of another. The first 101 and second 102 compartments havewalls 111 and are separated by separator 103. The separator 103 is inthermal contact with the first 101 and second 102 compartments. Thefirst compartment contains a pyrotechnic composition (not depicted) andthe second compartment 102 contains a metal hydride (not depicted). Anigniter 104 is interconnected with the first compartment 101. Theigniter 104 initiates reaction of the pyrotechnic composition. Thedevice 100 may further include an outlet 107 for the egress of hydrogengas generated in the second compartment 102. The outlet 107 isinterconnected with the second compartment 102. FIG. 3B further depictsintermediate thermal energy conductors 105 traversing through theseparator 103 with one distal end of the thermal energy conductor 105extending into the first compartment 101 and the other distal end of thethermal energy conductor 105 extending into the second compartment 102.

FIGS. 4A and 4B depict a device for generating hydrogen gas according tovarious embodiments as described in the above Summary and DetailedDescription and herein below. More specifically, FIGS. 4A and 4B depicta device 100 having first 101, second 102 and third 130 compartments,with the second compartment 102 positioned between the first compartment101 and a third 130 compartments. The first 101, second 102 and third130 compartments have walls 111. A separator 103 separates the first 101and second 102 compartments. The separator 103 is in thermal contactwith the first 101 and second 102 compartments. A partition 132separates the second 102 and third 130 compartments. The firstcompartment 101 contains a pyrotechnic composition (not depicted); thesecond compartment 102 contains a metal hydride (not depicted); and thethird compartment 130 contains a balloon 131. An outlet 107 for theegress of hydrogen gas generated in the second compartment 102interconnects the second compartment 102 with the balloon 131.Furthermore, a heat exchanger 106 is interconnected to the outlet 107.The heat exchanger 106 cools the hydrogen gas exiting the secondcompartment 102 through outlet 107. An igniter 104 is interconnectedwith the first compartment 101. The igniter 104 initiates reaction ofthe pyrotechnic composition.

FIG. 4B further depicts intermediate thermal energy conductors 105 and adata collection module 133. The intermediate thermal energy conductors105 traverse through the separator 103 with one distal end of thethermal energy conductors 105 extending into the first compartment 101and the other distal end of the thermal energy conductors 105 extendinginto the second compartment 102. The data collection module 133 isconfigured to collect data for determining one or both of meteorologicaland terrestrial activities or conditions.

FIG. 5 depicts a device for generating hydrogen gas according to variousembodiments as described in the above Summary and Detailed Descriptionand herein below. More specifically, FIG. 5 depicts a device 100 havingfirst compartment 101 and second compartment 102, with the secondcompartment 102 encased in the first compartment 101. Positioned betweena third compartment 130 and the first compartment 101 is a datacollection module compartment 139. The first compartment 101, the thirdcompartment 130, and the data collection module compartment 139 havewalls 111. Separator 103 separates the first 101 and second 102compartments. The separator 103 is in thermal contact with the first 101and second 102 compartments. A partition 137 separates the second 102compartment and the data collection module compartment 139, and abarrier 138 separates the data collection module compartment 139 andthird compartment 130. The first compartment contains a pyrotechniccomposition (not depicted) and vent 135; the second compartment 102contains a metal hydride (not depicted); the third compartment 130contains a balloon 131 (not depicted); and the data collection modulecompartment 139 contains a data collection module 133 (not depicted). Anoutlet 107 for the egress of hydrogen gas generated in the secondcompartment 102 interconnects the second compartment 102 with theballoon 131. Furthermore, a heat exchanger 106 is interconnected to theoutlet 107. The heat exchanger 106 cools the hydrogen gas exiting thesecond compartment 102 through outlet 107. An igniter 104 isinterconnected with the first compartment 101. The igniter 104 initiatesreaction of the pyrotechnic composition.

Examples

The thermite reaction produces a large amount of heat in a short periodof time from a small volume of material. In an example implementationusing 38.5 g of thermite, the thermite reaction releases nearly 152,988J of energy over a period of about 10 seconds, or 15,299 J/sec.

Further to the volume efficiency of this approach, the hydrogen source,a metal hydride, is a very volume efficient source of hydrogen gas (H₂).A test filling of a balloon was performed. The final balloon volume wasmeasured at approximately 42 liters at the conclusion of the test. Givenambient pressure (0.82 atm) and temperature (300 degrees Kelvin or 27degrees Celsius), this corresponded to 1.40 mole of hydrogen beingproduced. Working from the reactions presented above, the 30 g of LiAlH₄should have yielded 1.18 moles of hydrogen if only the first tworeactions went to completion (which is the design criterion), or 1.57moles if all three reactions went to completion. The measured value of1.40 moles is right between these values and right where it is desiredto be. This result means that the reactor is easily completing therequired first two decomposition steps, and via the third decompositionstep is generating additional hydrogen beyond that required in thedesign. This would be expected given the temperature data gatheredduring the experiment, which showed temperature climbing above thatrequired to initiate the third decomposition step.

A number of variations and modifications of the disclosure can be used.It would be possible to provide for some features of the disclosurewithout providing others.

The present disclosure, in various aspects, embodiments, andconfigurations, includes components, methods, processes, systems and/orapparatus substantially as depicted and described herein, includingvarious aspects, embodiments, configurations, sub-combinations, andsubsets thereof. Those of skill in the art will understand how to makeand use the various aspects, aspects, embodiments, and configurations,after understanding the present disclosure. The present disclosure, invarious aspects, embodiments, and configurations, includes providingdevices and processes in the absence of items not depicted and/ordescribed herein or in various aspects, embodiments, and configurationshereof, including in the absence of such items as may have been used inprevious devices or processes, e.g., for improving performance,achieving ease and/or reducing cost of implementation.

The foregoing discussion of the disclosure has been presented forpurposes of illustration and description. The foregoing is not intendedto limit the disclosure to the form or forms disclosed herein. In theforegoing Detailed Description for example, various features of thedisclosure are grouped together in one or more, aspects, embodiments,and configurations for the purpose of streamlining the disclosure. Thefeatures of the aspects, embodiments, and configurations of thedisclosure may be combined in alternate aspects, embodiments, andconfigurations other than those discussed above. This method ofdisclosure is not to be interpreted as reflecting an intention that theclaimed disclosure requires more features than are expressly recited ineach claim. Rather, as the following claims reflect, inventive aspectslie in less than all features of a single foregoing disclosed aspect,embodiment, or configuration. Thus, the following claims are herebyincorporated into this Detailed Description, with each claim standing onits own as a separate preferred embodiment of the disclosure.

Moreover, though the description of the disclosure has includeddescription of one or more aspects, embodiments, or configurations andcertain variations and modifications, other variations, combinations,and modifications are within the scope of the disclosure, e.g., as maybe within the skill and knowledge of those in the art, afterunderstanding the present disclosure. It is intended to obtain rightswhich include alternative aspects, embodiments, and configurations tothe extent permitted, including alternate, interchangeable and/orequivalent structures, functions, ranges or steps to those claimed,whether or not such alternate, interchangeable and/or equivalentstructures, functions, ranges or steps are disclosed herein, and withoutintending to publicly dedicate any patentable subject matter.

What is claimed is:
 1. A device, comprising: a separator capable oftransferring thermal energy; a first compartment, in thermal contactwith the separator, comprising a pyrotechnic composition and an igniter;and a second compartment in thermal contact with the separator, whereinthe separator is positioned between and mutually isolates the first andsecond compartments for the transfer of thermal energy to a metalhydride within the second compartment to release hydrogen gas.
 2. Thedevice of claim 1, wherein the pyrotechnic composition comprises apowder metal oxide and a powder metal and wherein the separator passesat least some of the thermal energy generated in the first compartmentto the second compartment.
 3. The device of claim 2, wherein the powdermetal oxide is selected from the group consisting essentially of iron(III) oxide (Fe₂O₃), iron (II,III) oxide (Fe₃O₄), copper (I) oxide(Cu₂O), copper (II) oxide (CuO), tin (IV) oxide (SnO₂), lead (IV) oxide(PbO₂), manganese (IV) oxide (MnO₂), manganese (III) oxide (Mn₂O₃),chromium (III) oxide (Cr₂O₃), cobalt (II) oxide (CoO), nickel (II) oxide(NiO), and vanadium (V) oxide (V₂O₅), and mixtures thereof, and whereinthe powder metal is selected from the group consisting essentially ofaluminum (Al), magnesium (Mg), zinc (Zn) and mixtures thereof.
 4. Thedevice of claim 1, wherein the metal hydride is selected from the groupconsisting essentially of lithium aluminum hydride (LiAlH₄), sodiumaluminum hydride (NaAlH₄), potassium aluminum hydride (KAlH₄), lithiumborohydride (LiBH₄), sodium borohydride (NaBH₄), potassium borohydride(KBH₄), lithium hydride (LiH), sodium hydride (NaH), potassium hydride(KH), magnesium hydride (MgH₂), calcium hydride (CaH₂) and mixtures andcomposites thereof.
 5. The device of claim 1, wherein the igniterinitiates the reaction of the pyrotechnic composition, and wherein theigniter is initiated by one or more of a spark, heat, flame, andfriction.
 6. The device of claim 1, wherein the first compartmentcomprises one of a ceramic or steel, wherein the second comprises one ofaluminum or steel, wherein the separator comprises steel, and whereinthe separator transfers at least more than about 30% of the thermalenergy generated by reaction of the pyrotechnic composition.
 7. Thedevice of claim 1, wherein the first compartment has a first compartmentvolume, wherein the second compartment has a second compartment volume,wherein the device has device volume, wherein the device volume is thesum of the first and second compartment volumes.
 8. The device of claim7, wherein the device releases in no more than about 60 seconds one of:i) more than about 4.6 moles of hydrogen gas per liter of the devicevolume; ii) about 6.2 moles of hydrogen gas per liter of the devicevolume; iii) more than about 7.3 moles of hydrogen gas per liter of thedevice volume; or iv) about 9.7 moles of hydrogen gas per liter of thedevice volume.
 9. The device of claim 7, wherein the device releases inabout 300 seconds from about 4.6 to about 6.2 moles of hydrogen gas perliter of the device volume.
 10. A device, comprising: a separatorcomprising a heat resistant and thermally conductive material; and firstand second compartments, wherein the separator: (i) is in thermalcontact with the first and second compartments; (ii) is positionedbetween and mutually isolates the first and second compartments; and(iii) transfers thermal energy from the first compartment to a metalhydride contained within the second compartment to thermally decomposethe metal hydride, and wherein the first compartment comprises apyrotechnic composition and an igniter.
 11. The device of claim 10,wherein the pyrotechnic composition comprises a powder metal oxide and apowder metal and wherein the separator passes at least some of thethermal energy generated in the first compartment to the secondcompartment.
 12. The device of claim 11, wherein the powder metal oxideis selected from the group consisting essentially of iron (III) oxide(Fe₂O₃), iron RIM oxide (Fe₃O₄), copper (I) oxide (Cu₂O), copper (II)oxide (CuO), tin (IV) oxide (SnO₂), lead (IV) oxide (PbO₂), manganese(IV) oxide (MnO₂), manganese (III) oxide (Mn₂O₃), chromium (III) oxide(Cr₂O₃), cobalt (II) oxide (CoO), nickel (II) oxide (NiO), and vanadium(V) oxide (V₂O₅), and mixtures thereof, and wherein the powder metal isselected from the group consisting essentially of aluminum (Al),magnesium (Mg), zinc (Zn) and mixtures thereof.
 13. The device of claim11, wherein the metal hydride is selected from the group consistingessentially of lithium aluminum hydride (LiAlH₄), sodium aluminumhydride (NaAlH₄), potassium aluminum hydride (KAlH₄), lithiumborohydride sodium borohydride (NaBH₄), potassium borohydride (KBH₄),lithium hydride (LiH), sodium hydride (NaH), potassium hydride (KH),magnesium hydride (MgH₂), calcium hydride (CaH₂) and mixtures andcomposites thereof.
 14. The device of claim 11, wherein the igniterinitiates the reaction of the pyrotechnic composition, and wherein theigniter is initiated by one or more of a spark, heat, flame, andfriction.
 15. The device of claim 11, wherein the first compartmentcomprises one of a ceramic or steel, wherein the second comprises one ofaluminum or steel, wherein the separator comprises steel, and whereinthe separator transfers at least more than about 30% of the thermalenergy generated by reaction of the pyrotechnic composition.
 16. Thedevice of claim 11, wherein the first compartment has a firstcompartment volume, wherein the second compartment has a secondcompartment volume, wherein the device has device volume, wherein thedevice volume is the sum of the first and second compartment volumes.17. The device of claim 16, wherein the device releases in no more thanabout 60 seconds one of: i) more than about 4.6 moles of hydrogen gasper liter of the device volume; ii) about 6.2 moles of hydrogen gas perliter of the device volume; iii) more than about 7.3 moles of hydrogengas per liter of the device volume; or iv) about 9.7 moles of hydrogengas per liter of the device volume.
 18. The device of claim 16, whereinthe device releases in about 300 seconds from about 4.6 to about 6.2moles of hydrogen gas per liter of the device volume.
 19. A device,comprising: a metal hydride; and mutually isolated and separated firstand second compartments in thermal contact with each other by aseparator, wherein the second compartment contains the metal hydride,wherein the first compartment comprises a pyrotechnic composition and anigniter, and wherein the separator is position between and mutuallyisolates the pyrotechnic composition and the metal hydride and where inthe separator is an initiator of thermal decomposition of the metalhydride.
 20. The device of claim 19, wherein the pyrotechnic compositioncomprises a powder metal oxide and a powder metal and wherein theseparator passes at least some of the thermal energy generated in thefirst compartment to the second compartment.
 21. The device of claim 20,wherein the powder metal oxide is selected from the group consistingessentially of iron (III) oxide (Fe₂O₃), iron (II,III) oxide (Fe₃O₄),copper (I) oxide (Cu₂O), copper (II) oxide (CuO), tin (IV) oxide (SnO₂),lead (IV) oxide (PbO₂), manganese (IV) oxide (MnO₂), manganese (III)oxide (Mn₂O₃), chromium (III) oxide (Cr₂O₃), cobalt (II) oxide (CoO),nickel (II) oxide (NiO), and vanadium (V) oxide (V₂O₅), and mixturesthereof, and wherein the powder metal is selected from the groupconsisting essentially of aluminum (Al), magnesium (Mg), zinc (Zn) andmixtures thereof.
 22. The device of claim 19, wherein the metal hydrideis selected from the group consisting essentially of lithium aluminumhydride (LiAlH₄), sodium aluminum hydride (NaAlH₄), potassium aluminumhydride (KAlH₄), lithium borohydride (LiBH₄), sodium borohydride(NaBH₄), potassium borohydride (KBH₄), lithium hydride (LiH), sodiumhydride (NaH), potassium hydride (KH), magnesium hydride (MgH₂), calciumhydride (CaH₂) and mixtures and composites thereof.
 23. The device ofclaim 19, wherein the igniter initiates the reaction of the pyrotechniccomposition, and wherein the igniter is initiated by one or more of aspark, heat, flame, and friction.
 24. The device of claim 19, whereinthe first compartment comprises one of a ceramic or steel, wherein thesecond comprises one of aluminum or steel, wherein the separatorcomprises steel, and wherein the separator transfers at least more thanabout 30% of the thermal energy generated by reaction of the pyrotechniccomposition.
 25. The device of claim 19, wherein the first compartmenthas a first compartment volume, wherein the second compartment has asecond compartment volume, wherein the device has device volume, whereinthe device volume is the sum of the first and second compartmentvolumes.
 26. The device of claim 25, wherein the device releases in nomore than about 60 seconds one of: i) more than about 4.6 moles ofhydrogen gas per liter of the device volume; ii) about 6.2 moles ofhydrogen gas per liter of the device volume; iii) more than about 7.3moles of hydrogen gas per liter of the device volume; or iv) about 9.7moles of hydrogen gas per liter of the device volume.
 27. The device ofclaim 25, wherein the device releases in about 300 seconds from about4.6 to about 6.2 moles of hydrogen gas per liter of the device volume.